Workbasket for use in heat-treating furnace

ABSTRACT

A workbasket for use in a heat-treating furnace including a plurality of trays that are mounted in spaced vertical relation, the spacing of the trays providing for free circulation of a heated atmosphere within the furnace, and thereby insuring an even distribution of heat in and around articles located in the trays.

United States Patent Pine et al.

Feb. 15, I972 WORKBASKET FOR USE IN HEAT- TREATING FURNACE Inventors: Wilson C. Pine, Cranston; Herbert W. Westeren, Barrington; William H. Kimball, Providence, all of RI.

Assignee: C. I. Hayes Inc., Cranston, RI.

Filed: Dec. 15, 1969 App]. No: 884,961

Related U.S. Application Data Division of Ser. No. 796,085, Feb. 3, 1969, Pat. No. 3,522,357.

U.S. CI ..263/47, 220/23.83

Field of Search ..263/47, 47 A; 220/19, 2383 References Cited UNITED STATES PATENTS Sammon et a1. ..263/47 X FOREIGN PATENTS OR APPLICATIONS 564,724 10/1958 Canada ..263/47 A Primary Examinerlohn J. Camby AtmrneySaIter and Michaelson [57] ABSTRACT A workbasket for use in a heat-treating furnace including a plurality of trays that are mounted in spaced vertical relation, the spacing of the trays providing for free circulation of a heated atmosphere within the furnace, and thereby insuring an even distribution of heat in and around articles located in the trays.

5 Claims, 7 Drawing Figures WILSON C. PINE BY HERBERT W WESTEREN ATTORNEYS ILLIAM .KIMBALL WORKBASKET FOR USE IN HEAT-TREATING FURNACE BACKGROUND OF THE INVENTION This is a division of a copending application Ser. No. 796,085 entitled VACUUM FURNACE HAVING A LIQUID QUENCH AND A VERTICALLY MOVABLE WORK HOLDER, filed Feb. 3, 1969, now US. Patent No. 3,522,357. As set forth in the aforesaid copending application, the work basket, as embodied in the present invention, is adapted for particular use in industrial heat treating furnaces and particularly in vacuum heat-treating furnaces.

In the heat treatment of certain metals under vacuum and at elevated temperatures, the nature of these metals in such that the time that the metal is subjected to a given temperature is critical. In the prior known basket construction for heat-treating metals under vacuum, the articles to be hearttreated were normally placed in a basket without regard to the distribution of the articles therein or to the manner in which a conditioning atmosphere was circulated therearound in the heating chamber of the furnace. Thus, in highly dense loads, the outside layers of the articles, that is those nearest to the furnace heating elements, reached the critical temperature first, and naturally, in order to properly heat the articles located interiorly of the work load, the outside articles were retained at the elevated temperature for a relatively long period of time. Such a condition sometimes caused the articles being hearttreated to sinter or fuse together. Further, ina heavy load, the workpieces or articles on or near the bottom of the work load were subjected to the weight of the articles above, thereby increasing the pressure on the lowermost pieces, which, in conjunc tion with the heat, caused the sintering in that area to be more prevalent. In vacuum furnaces which incorporate a quenching liquid therein, quenching uniformity is also affected when a load of treated articles is dropped from the heating zone into the quenching liquid. It is understood that a highly dense mass tends to slow down the quench cycle, and in turn affects the metallurgical characteristics of the metal since the outer pieces are cooled more rapidly than the inner ones.

SUMMARY OF THE INVENTION The present invention is adapted to reduce the mass concentration of articles in a work holder as employed in a furnace construction and, as a result, further provides for the reduction of pressure on the articles located in the work basket during the heat treating cycle. The workbasket, as embodied herein, comprises a plurality of article-holding trays located in spaced-apart, stacked, vertical relation, each of the trays including a base for locatingit in its spaced-apartrelation. The spacing of the trays provides for uninhibited flow of the conditioning atmosphere during the heat treating operation, and since a plurality of trays are employed in the complete workbasket, a concentration of the articles in a single area is avoided. Each of the trays is further provided with an annular compartment that enables the articles to be evenly distributed therein so that the entire surface area of the articles can be effectively heat treated during the heat-treating cycle.

Accordingly, it is an object of the present invention to provide a work basket for use in a furnace construction that includes a plurality of article-holding trays that are located in spaced-apart vertical relation.

Another object of the invention is to provide a workbasket for a furnace construction that includes a frame on which a plurality of trays are mounted in stacked relation, the trays being formed of a metallic mesh material to promote free flow of a heattreating atmosphere, and further including means for effectively spacing the trays from each other as mounted on the frame.

Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.

DESCRIPTION OF THE DRAWING In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:

FIG. 1 is a perspective view of the workbasket embodied in the present invention;

FIG. 2 is a perspective view of the frame on which the trays embodied in the subject invention are mounted to form the assembly illustrated in FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a bottom plan view of the frame illustrated in FIG.

FIG. 5 is a sectional view taken along line 55 in FIG. 4; FIG. 6 is a perspective view of one of the trays that form a part of the workbasket assembly illustrated in FIG. I", and

FIG. 7 is an enlarged fragmentary sectional view showing the interrelation of the adjacent trays in the subject invention.

DESCRIPTION OF THE INVENTION The present invention has particular application in the heat treatment of metallic articles in a vacuum furnace of the type as disclosed in copending application Ser. No. 796,085, of which the present application is a division. However, it is contemplated that the work basket, as disclosed herein, may be utilized in various forms of heat-treating furnaces and, in this connection, it is contemplated that the work basket may be employed in heat-treating furnaces that do not require a liquid quench. As set forth in the copending application Ser. No. 796,085, the workbasket is mounted for-vertical movement within the furnace, which provides for transfer of the basket from the heating zone to a quench zone. Although the work basket of the subject invention is particularly adaptable for movement in a vertical direction, the broad concept of the invention, as will be described, does not require that the workbasket be moved vertically or that it be moved at all during the heat treating cycle.

Referring now to the drawing and particularly to FIG. I, the workbasket embodied in the present invention is illustrated and is generally indicated at 180. As described, the workbasket is designed to promote effective heattreating of the articles located therein, and in those instances when the work basket is utilized in a vacuum furnace having a liquid quench, it is further designed to promote effective quenching of the articles carried therein. For this purpose, the workbasket includes a plurality of work trays generally indicated at 182, that are positioned in spaced vertical relation. The work trays 182 are stacked on a frame, generally indicated at 184, which, as shown in FIGS. 2, 3 and 4, include spaced members I86 that are located at 60 intervals and that are welded together at the center point of the frame. Vertical supports 188 are slotted at the lower ends thereof and are interfitted over alternately positioned base members 186. Bottom web members I90 are welded between a support 188 and an adjacent base member 186, as indicated in FIG. 9, to firmly anchor the supports 188 in place. Upper web members 192 are joined between the supports 188 at the upper ends thereof and cooperate with the web members to fix the supports 188 in position relative to each other.

As shown in FIGS. 10, 11 and 12, each of the work trays 182 includes a circular bottom wall 194 formed of a mesh material in which a central opening 196 is located. Joined to the outer marginal edge of the bottom wall 196 is an outer annular sidewall 198 of a mesh material, while joined to the marginal edge of the central opening 196, is an inner annular side wall 200. The inner and outer annular sidewalls I98 and 200 cooperate with the bottom wall 196 to define an annular compartment 202 in which the articles to be heartreated are received.

In order to vertically space the work trays I82 apart, spacer elements 204 are provided and are secured within the annular compartment 202 of eachtray to the .puter annular sidewall 198 and to the bottom wall 194 at 60 intervals. Guards 206 of channel shape are secured beneath the bottom wall 194 in alignment with the spacer elements 204 and are dimensioned to receive the spacer element of a below located tray therein. It is seen that after the an'nular compartment 202 of a tray 182 is filled with the articles to be heat-treated, the tray is mounted on the frame 184 by sliding it over the support 188, the central opening'196 receiving the supports 188 therethrough. The guards 206 of the bottom tray rest on the base members 186, and as each succeeding tray is mounted on the frame, the spacer elements 204 receive the guards 206 thereon to vertically space the trays 182 as illustrated in FIG. 1. If the work basket 180 is to be utilized in a furnace of the type as illustrated and described in copending application Ser. No. 796,085, it will be necessary to move the workbasket in a vertical direction and for this purpose, a tube 208 is fixed to the upper web members 192 and projects thereabove as also illustrated in FIG. 1. A hole 210 is formed in the upper end of the tube 208 and receives a clevis pin (not shown) for locking the workbasket to a chain or other similar elevating device.

It is seen that in the heat treatment of the articles located in the workbasket 182, the heat may circulate through the spaces defined between the trays and through the mesh material from which the trays are constructed, thereby avoiding uneven heating and preventing sintering or fusing of the articles. Further, it is seen that since the articles are separated in the trays, the load on the articles isrelieved, thereby avoiding sintering of the pieces that would normally be located at the bottom of a work holder. When the workbasket is used in a furnace having a liquid quench, quenching is more uniform in contrast to a highly dense mass which would tend to slow down the quench time thereby affecting the metallurgical characteristics of the metal. However, in the work basket as described herein, the outermost articles in the basket are cooled as rapidly as those located inwardly thereof, and thus since the mass concentration is reduced, the load and pressure on the articles located in the basket are relieved. As a result, a more uniform finished article is realized when the workbasket of the subject invention is employed.

We claim:

1. A workbasket for use in heattreating metallic articles, comprising a plurality of article holding trays located in spaced-apart, stacked vertical relation and including spaced annular walls that define an annular compartment, a plurality of vertically extending posts fixed in each of said compartments and projecting above the walls thereof, a plurality of guards fixed beneath each of said trays in alignment with said posts, the guards of one tray engaging the posts of an adjacent tray for locating said trays in oriented stacked relation, and a frame on which said trays are mounted in stacked relation, said frame including vertical support means for receiving said trays in vertically stacked relation thereon.

2. A workbasket for use in heat treating metallic articles comprising a plurality of article holding trays located in spaced-apart, stacked vertical relation, means secured to said trays for locating them in their spaced-apart relation, each of said trays including an outer annular wall and an inner annular wall, an annular compartment being formed between said annular walls for receiving said metallic articles therein, and a frame on which said trays are mounted in stacked relation, said frame including a plurality of spaced vertical supports that are received within said inner annular wall of each tray as the trays are mounted on said frame.

3. A workbasket as set forth in claim 2, said annular walls being formed of a wire mesh material that promotes the free circulation of heat therethrough and into contact with said articles as located in the compaftments of said stacked trays.

4. A workbasket as set forth in claim 2, said frame further including a plurality of base members that are interconnected and that receive said vertical supports thereon in fixed relation.

5. A workbasket as set forth in claim 2, said locating means including a plurality of spacer elements fixed in said trays and pro'ecting thereabove, and a plurality of guards fixed beneath sat trays in alignment with said spacer elements, the guards of one tray engaging the spacer elements of an adjacent tray for locating said trays in oriented stacked relation. 

1. A workbasket for use in heattreating metallic articles, comprising a plurality of article holding trays located in spaced-apart, stacked vertical relation and including spaced annular walls that define an annular compartment, a plurality of vertically extending posts fixed in each of said compartments and projecting above the walls thereof, a plurality of guards fixed beneath each of said trays in alignment with said posts, the guards of one tray engaging the posts of an adjacent tray for locating said trays in oriented stacked relation, and a frame on which said trays are mounted in stacked relation, said frame including vertical support means for receiving said trays in vertically stacked relation thereon.
 2. A workbasket for use in heat treating metallic articles comprising a plurality of article holdiNg trays located in spaced-apart, stacked vertical relation, means secured to said trays for locating them in their spaced-apart relation, each of said trays including an outer annular wall and an inner annular wall, an annular compartment being formed between said annular walls for receiving said metallic articles therein, and a frame on which said trays are mounted in stacked relation, said frame including a plurality of spaced vertical supports that are received within said inner annular wall of each tray as the trays are mounted on said frame.
 3. A workbasket as set forth in claim 2, said annular walls being formed of a wire mesh material that promotes the free circulation of heat therethrough and into contact with said articles as located in the compartments of said stacked trays.
 4. A workbasket as set forth in claim 2, said frame further including a plurality of base members that are interconnected and that receive said vertical supports thereon in fixed relation.
 5. A workbasket as set forth in claim 2, said locating means including a plurality of spacer elements fixed in said trays and projecting thereabove, and a plurality of guards fixed beneath said trays in alignment with said spacer elements, the guards of one tray engaging the spacer elements of an adjacent tray for locating said trays in oriented stacked relation. 